I had two lines brought to the house. They used a new (at least to me) Telephone
Network box and there are only red and green hook up. The one line will be just
for voice and the other is for fax and 56k modem.
On a normal two pair you have red, green, yellow, and black. My question is
(just talking about one line now) where do the yellow and black connect to?
I agree with Colby.
The Yellow/Black are usually for a second telephone line. Very
occasionally they might get used if the Red/Green went faulty
(but in that case it's likely the whole entrance cable is
damaged). Also occasionally the Yellow/Black might be used for
miscellaneous purposes. For example on two party telephone lines,
which are rare these days it is necessary to have a ground wire
to the telephone set for the ringer/bell. So the installer would
use one of those to the part line telephone, for that. The
Red/Green is normally the 'telephone pair' which goes back to the
telephone exchange /switching centre on which you get dial tone,
do your dialling (well it's usually touch-tone these days) and
receive ringing when someone calls you.
With private/indidvidual lines you don't need a ground connection
to each phone set. But the telco will usually have a 'protector'
either just inside or outside the house/building that is grounded
for the purpose of shunting anything unauthorized voltages or
minor lightning to ground for safety.
What was throwing me was that the old lines were party lines (which were stopped
back in 1982) on the house and I knew that it was not just red and green.
Again thank you group for your help.
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